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The accurate determination of residual stresses has a crucial role in understanding the complex interactions between microstructure, mechanical state, mode(s) of failure, and structural integrity. Moreover, the residual stress management concept contributes to industrial applications, aiming to improve the product's service performance and life cycle. In this regard, the industry requests rapid, efficient, and modern methods to identify and control the residual stress state. This review article contains three main sections. The first section covers different residual stress determination methods and reports the advancements over the recent decade. The second section includes the role of residual stresses in the performance of a broad range of materials including metallic alloys, polymers, ceramics, composites, and biomaterials. This is presented by classifying different science areas dealing with residual stresses into two main groups, including “origins” and “effects” of residual stresses. The range of topics covered are “welding, machining, curing/cooling, and spray coating processes,” “medical and dental sciences,” and “fatigue and fracture mechanisms.” The third section summarizes various strategies to effectively control residual stresses through different manufacturing procedures. It is hoped that the data provided herein serves as a valuable up-to-date reference for engineers and scientists in the field of residual stress.

The effect of angle and thickness of plies are investigated on the fracture energy release rate (ERR) in mode II of carbon/epoxy prepreg laminated composites using finite element modelling. The ply’s angle of = 0o, 22.5o, 30o, 45o, 60o, and 90o with 4 different thicknesses are investigated. The finite element modelling is done using the virtual crack closure technique (VCCT) to evaluate the asymmetric effect. The overall stiffness of the laminates is designed to have the least difference from the Mode II standard ASTM test. The results show that by increasing the thickness of the plies, the asymmetric effect and consequently the mode I/Mode II loading contribution is increased. The results show that ERR is decreased by increasing both angle and thickness of the plies. This understanding can help in designing composite materials with better delamination resistant properties under different loadings such as low-velocity impact.

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Composite materials and structures have witnessed substantial developments over the last few decades. Mechanochromic polymers are a new class of smart composites with the ability to self-report their health condition on-line. The design mechanism in these materials is such that initiation of any force or mechanical stimuli leads to a color change in the composite surface, so that the damage can be monitored and repaired at early stages, resulting in longer fatigue lifetime of the structures. This paper aims to design a novel mechanochromic composite sensor to be used as an overload/damage indication tool on the surface of skateboards. The smart composite skateboard with damage monitoring sensor is then manufactured and tested under different loading conditions. The results clarify that the proposed skateboard could well detect and visualize the damage on the surface/back faces while it is light-weight, high-performance and environmentally friendly. It is also highlighted that the mechanochromic sensors can well act as a structural health monitoring (SHM) system in other composite structures such as wind turbine blades, automotive panels etc.

This paper aims to study the feasibility of smart thin-ply hybrid glass/carbon sensors in quasi-static impact damage detection and analyse different design strategies to achieve an optimal sensor performance. A set of carbon fibre reinforced polymer (CFRP) specimens was manufactured, and the hybrid sensing layers were attached and evaluated. New architectures of hybrid sensing layers are proposed using woven prepregs and introducing pre-cuts to increase stress concentration. The sensors are used under indentation to detect the damage. Outcomes established key design insights, which will be used further in developing the self-sensing technology and may result in more sustainable composite structures that are light-weight, easy to inspect and last longer.

This paper focuses on the application of the first-order shear deformation theory (FSDT) to thermo-elastic static problems of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) cylindrical pressure vessels. A symmetric displacement field is considered as unknown function along the longitudinal direction, whereas a linear distribution is assumed along the thickness direction. The cylindrical pressure vessels are subjected to an inner and outer pressure under a temperature increase. Different patterns of reinforcement are applied as distribution of CNTs. The effective material properties of FG-CNTRC cylindrical pressure vessels are measured based on the rule of mixture, whereas the governing equations of the problem are here derived through the principle of virtual works. A large parametric investigation studies the effect of some significant parameters, such as the pattern and volume fraction of CNTs, on the longitudinal distribution of deformation, strain and stress components, as useful tool for practical engineering applications.